Application Of Poly （Ionic Liquid）s In Emulsions Separation

At present,excessive discharge of emulsions,especially oil/water emulsions from domestic and industrial processes,poses a great threat to human health and ecological balance.Common demulsification methods include various physical,biological and chemical methods.As an effective demulsification method,chemical demulsification has been widely used in industry.In recent years,ionic liquids（ILs）,as a green chemical,have been used as a commercial demulsifier because of their good thermal stability and amphiphilic properties.However,as a homogeneous demulsifiers,they face the problem of difficult separation and recovery.This thesis is devoted to the design and synthesis of a highly recyclable heterogeneous demulsifier,and the synthesis of poly（ionic liquids）（PILs）with swelling properties to achieve high efficiency demulsification.The main contents of the dissertation were as follows:（1）The research progress of emulsion separation and the research status of demulsification of ILs and PILs were summarized.（2）The imidazolium PILs with different alkyl chain lengths were synthesized by free radical initiation polymerization,which n-vinyl imidazolium ILs was used as monomer and divinylbenzene was used as cross linker.The structures and properties of prepared PILs were characterized by¹³C MAS NMR,FT-IR,and TGA.The swelling capacities of PILs with different structures in oil-in-water emulsion and water were investigated.It was found that the swelling capacities of PILs in oil-in-water emulsion decreased with the change of side chain substituents from n-ethyl,n-butyl,n-hexyl to n-octyl.PILs with different substituent chain lengths were used in oil-in-water emulsions with sodium dodecyl sulfate as emulsifiers.It was found that the swelling capacities of PILs were positively correlated with demulsification efficiencies.The concentration of dodecyl sulfate ions and Br^-in water phase after demulsification was measured by HPLC and IC to explore the demulsification mechanism of PIL.The results showed that anion exchange reaction occurred between the PILs and emulsifier sodium dodecyl sulfate.The PILs could be recycled by ion exchange with Na Br solution and the demulsification efficiencies did not show significant decline during 5 times of recycling.（3）P[VEIm]Br@4（?）zeolite was synthesized by free radical initiation polymerization,which 1-vinyl-3-ethylimidazolium bromide was used as monomer and 4（?）zeolite was used as substrate.At the same time,hydrophilic membrane and oil-hydrophilic membrane were synthesized.The T type device was built by integrating P[VEIm]Br@4（?）zeolite,hydrophilic membrane and hydrophobic membrane to realize demulsification and oil-water separation integration.It was found that the demulsification efficiency of various oil/water emulsions was above99%,and water and oil could be collected at the same time.T type device also showed excellent demulsification performance in demulsification tests of different oil-water ratio emulsion and acid,alkali and salt emulsion.Meanwhile,through continuous demulsification test,the maximum demulsification amount of P[VEIm]Br@4（?）zeolite was 133 m L/g,and the emulsion flux of T type device was1083 L·m^-2·h^-1.